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Hotspots not the best way to preserve biodiversity

By Catherine Brahic

Conservationists must make better choices of the areas they focus their protection efforts on, say researchers.

The concept of “hotspots” of biodiversity, which organisations like Conservation International have been using since the late 1980s, is too simple to be effective, argue Gerardo Ceballos, at the National Autonomous University of Mexico (UNAM), and Paul Ehrlich, at Stanford University, US.

It is generally accepted that there are three types of hotspots&colon; hotspots of endemic species that are found only in that area, hotspots of endangered species and hotspots of richness, which contain a greater number of different species than most regions.

Ceballos and Ehrlich mapped the top 2.5% hotspots of each type and looked to see how much they overlapped. Very little was the answer – of all the species found in hotspots, only 16% were found in all three types.

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The researchers then looked at overlap within the hotspots, i.e. they sought out specific areas within the hotspots which contained the highest number of unique species. Based on this, they propose “optimisation algorithms” to help guide conservation efforts. These are mathematical techniques that help figure out the maximum number of species that can be protected by the minimum number of sites.

“This way, you can accomplish more protection with less area,” explains Ceballos.

Intensity of hunting

However, Ceballos emphasises that conservation needs to be “as complex as possible”, using lots of approaches. For example, he advocates better land management both within and outside hotspots.

He cites the Costa Rica, where a combination of education and government bans appears to have resulted in a drop in the intensity of hunting. “We have found that only 7% to 8% of the forest is left in Costa Rica, but around 70% of mammals are still there,” says Ceballos.

Jeffrey McNeely, chief scientist at the World Conservation Union (IUCN), agrees that a “Noah’s ark” strategy – trying to protect one sample of every species – makes little sense.

He points out that IUCN has called for protection of 10% of each biogeographic region, of which there are nearly 300 worldwide. But this only works if it is accompanied by appropriate land-management outside legally protected areas, he says.

“If you manage your land well, legally protecting 10% of the areas may be enough, but if you devastate the land that is not legally protected, 10% is not nearly enough,” says McNeely.

Easy concept

McNeely does believe that hotspots have played an important role in increasing the public profile of biodiversity and conservation. “People need to have a concept they can understand quickly and a hotspot is one such idea,” he says, adding international organisations have used the concept to convince governments to spend or raise money for conservation.

For instance, Conservation International demonstrated to Madagascar that its status as a biodiversity hotspot could enable economic development through tourism. “As a result Madagascar has expanded the number of protected areas, increased their education efforts and become more attractive as a tourist destination,” says McNeely.

Nonetheless, McNeely acknowledges that if the new research demonstrates the hotspot approach does not have a strong factual basis and suggests ways to better spend conservation funds, “then that’s very useful”.

Endangered species – Learn more about the conservation battle in our comprehensive special report.

Journal reference&colon; Proceedings of the National Academy of Sciences (vol 103, p 19374)